PTHH; Fe3O4 + 4H2\(\rightarrow\) 3Fe + 4H2O(1)
2Fe + 3Cl2 \(\rightarrow\)2FeCl3(2)
nFeCl3=\(\dfrac{32,5}{162,5}\)=0,2 mol
Theo PT(2); nFe=nFeCl3=0,2 mol
=> mFe=0,2.56=11,2=b
Theo PT(1) nfe3O4= 1/3nFe=0,0(6) mol
=> mFe3O4=0,0(6).232=15,4(6)g=a
PTHH:4H2+Fe3O4\(\underrightarrow{ }\)4H2O+3Fe(1)
2Fe+3Cl2\(\underrightarrow{ }\)2FeCl3(2)
Theo PTHH(2):325 gam FeCl3 cần 112 gam Fe
Vậy:32,5 gam FeCl3 cần 11,2 gam Fe
Theo PTHH(1):168 gam Fe cần 232 gam Fe3O4
Vậy:11,2 gam Fe cần 15,46 gam Fe3O4
Do đó:a=15,46(gam)
b=11,2(gam)